DE1595641B2 - PROCESS FOR THE PRODUCTION OF POLYCARBONATES - Google Patents

Description

. From US-PS 30 94 508 it is known, branched polycarbonates from bisphenols and special trivalent ones To manufacture phenols. In addition, the patent teaches that for the implementation of the Process conditions must be met that result in a product with a molecular weight from 200,000 to 500,000.

DT-AS 10 86 885 describes polycarbonates that are no longer thermoplastic.

The US-PS 29 50 266 describes the conversion of polycarbonates by means of polyphenols in crosslinked, insoluble and infusible products without thermoplastic properties.

Canadian Patent 715142 describes branched polycarbonates. The branching devices that can be used for this purpose are, however, of those of the present invention Invention different in terms of structure and reactivity. According to this one does not get any reproducible branched products such as B. for injection molding with tolerances of ± 0.003 in the relative Viscosity are required for values around 1,300.

The subject of the main patent 15 70 533 is a process for the production of high molecular weight, soluble and thermoplastic polycarbonates with increased stability of the melt strand compared to the usual polycarbonates, which are therefore particularly suitable for the production of products by the extrusion process. These polycarbonates are obtained by reacting bisphenols with phosgene or bischlorocarbonic acid esters in solution or by interfacial reaction between two solutions at temperatures up to 8O ⁰ C, or by reaction of bisphenols with carbonic acid diaryl esters in the melt, wherein, in the presence of the same time 0.01 to 2 , 0 mole percent more than divalent

nols and 0.1 to 8 mole percent monophenols, respectively based on the moles of bisphenols.

The more than dihydric phenols mentioned there for example are
5

Phloroglucine,

4,6-Dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2, ®

4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptane, ίο l, 3,5-tri- (4-hydroxyphenyl) -benzene,

l, l, l-tri- (4-hydroxyphenyl) -ethane and

2,2-bis- [4,4- (4,4'-dihydroxydiphenyl) -cyclo-

hexyl] propane.

It has now been found that such more than dihydric phenols in the specified amounts can be used with advantage that by reaction of p-alkyl-substituted Monophenols with free ortho positions with formaldehyde or formaldehyde-yielding compounds have been received.

A representative of this group of substances is trisphenol, made from p-cresol and formaldehyde, 2,6-bis- (2'-hydroxy-5'-methylbenzyl) -4-methyl-phenol. There may also be mentioned, for example: 2,6-bis- (2'-hydroxy-5'-isopropyl-benzyl) -4-isopropyl-phenol and bis- [2-hydroxy-3- (2'-hydroxy-5'-methylbenzyl) -5-methylphenyl] methane.

example

In a mixture of 3440 parts by weight of 2,2- (4,4'-dihydroxydiphenyl) propane, 18.4 parts by weight of 2,6-bis- (2'-hydroxy-5'-methyl-benzyl) -4-methylphenol , 50 parts by weight of p.-tert-butylphenol, 2813 parts by weight of 45% sodium hydroxide solution, 17 500 parts by weight of distilled water and 33 130 parts by weight of methylene chloride are introduced at 24 to 25 ° C for 2 hours with stirring in a nitrogen atmosphere, 1825 parts by weight of phosgene, while at the same time, from the 10th to 90th minute, 1300 parts by weight of 45% sodium hydroxide solution are added dropwise. After the phosgene has been passed in, 6 parts by weight of triethylamine are added. It is stirred for 1 hour. The organic phase is washed successively with 2% phosphoric acid, 2% sodium hydroxide solution, 2 more times with 2% phosphoric acid and finally with distilled water until the reaction is neutral. 7500 parts by weight of chlorobenzene are then added to the methylene chloride solution. Most of the methylene chloride is distilled off. After cooling, the polycarbonate gels, which is then crushed in a granulating machine to a powder-grain mixture. This is dried for 48 hours at 12O ⁰ C in a water jet vacuum. The relative viscosity of the polycarbonate is 1.38 (c = 5 g / l, T: 25 ° C., methylene chloride). To extrude a 50 cm long strand under the conditions as given in Examples 10 and 11 of the main patent, 90 seconds are required / 'gt.

Claims (1)

Claim: Process for the production of polycarbonates by reacting bisphenols with phosgene or bischlorocarbonic acid esters in solution or by interfacial reaction between two solutions at temperatures up to 80 ⁰ C or by reacting bisphenols with carbonic acid diaryl esters in the melt, in the presence of at the same time 0.01 to 2.0 mol percent more than dihydric phenols and 0.1 to 8 mol percent monophenols, based in each case on the moles of bisphenols, are converted, according to Patent 15 70 533, characterized in that the more than dihydric phenols used are those which are obtained by reacting para -alkyl-substituted monophenols with free ortho positions with formaldehyde or formaldehyde-yielding compounds have been obtained.